report vs newsletter

report and newsletter both are nouns.

Word	Noun	Adjective	Verb	Adverb
report	Yes	No	Yes	No
newsletter	Yes	No	No	No

As nouns, newsletter is a hyponym of report; that is, newsletter is a word with a more specific, narrower meaning than report:

report: a short account of the news
newsletter: report or open letter giving informal or confidential news of interest to a special group

Other hyponyms of report include newssheet, bulletin, communique, despatch, dispatch, urban legend, exclusive, scoop.

report (noun)	newsletter (noun)
the general estimation that the public has for a person	report or open letter giving informal or confidential news of interest to a special group
a short account of the news
the act of informing by verbal report
an essay (especially one written as an assignment)
a written document describing the findings of some individual or group
a written evaluation of a student's scholarship and deportment
a sharp explosive sound (especially the sound of a gun firing)

report (verb)	newsletter (verb)
to give an account or representation of in words
make known to the authorities
complain about; make a charge against
announce one's presence
announce as the result of an investigation or experience or finding
be responsible for reporting the details of, as in journalism